Field of Art
The present disclosure relates to an imaging apparatus having a function of performing focus detection by using a signal from an image sensor.
Description of the Related Art
It is known that when an imaging apparatus such as a digital camera performs automatic focusing (AF), any one of a plurality of focus detection areas arranged in advance is selected and used for AF. Examples of a method for selecting a focus detection area include a method for preferentially selecting a focus detection area in which there is likely to be a main object, like a screen center, and a method for preferentially selecting a focus detection area from which a focus detection result on a nearer side is obtained.
If focus detection areas are discretely arranged, the possibility for an intended object to fall outside the focus detection areas increases. Therefore, focus detection areas are desirably arranged at a high density. However, if the focus detection areas are reduced in size to increase the density, sufficient focus detection accuracy may not be obtained depending on the condition.
Japanese Patent Application Laid-Open No. 2010-160271 discusses a configuration to include a plurality of patterns (division patterns) of a plurality of divided areas into which a line sensor of a secondary image-forming optical system is divided, and switch the division patterns to increase the arrangement density of the focus detection areas. Japanese Patent Application Laid-Open No. 2010-160271 also discusses a configuration to perform focus detection by using all the division patterns during low-speed continuous imaging, and perform focus detection by switching the division patterns each time an image is captured during high-speed continuous imaging. In the low-speed continuous imaging, time available for AF per frame is long. In the high-speed continuous imaging, the time available for AF is short.
However, the configurations discussed in Japanese Patent Application Laid-Open No. 2010-160271 are predicated on focus detection using the line sensor of the secondary image-forming optical system. Such configurations do not take account of, for example, focus detection using a signal from an image sensor that generates an image for display or recording during capturing of a moving image.